How to build a pectoral fin: functional morphology and steady swimming kinematics of the spotted ratfish (<i>Hydrolagus colliei</i>)
Bibliographic record
Abstract
Aquatic flight is the primary locomotor mode for many animals, including penguins and other diving birds, turtles, and fishes, where labriform and rajiform swimming have been the focus of much interest. However, despite its interesting phylogenetic placement, little is known about the aquatic flight of the sister lineage to the elasmobranchs, the chimaerids. This study investigates the pectoral fin morphology of the spotted ratfish ( Hydrolagus colliei (Lay and Bennett, 1839)) as a possible factor underlying the kinematics of their steady swimming by comparing muscle mass, distribution, and abductor to adductor ratio with those of a closely related shark ( Squalus acanthias L., 1758). Despite fundamental differences in swimming mode, abductor to adductor muscle ratio did not differ between species (P = 0.49). However, the muscle ratio in the spotted ratfish was similar to the range determined in other flapping labriform swimmers. Ratfish had larger, distally placed pectoral fin muscles relative to body size than dogfish (P < 0.0001) possibly aiding in fine control. Stroke amplitude remained constant across body size (P = 0.26) and relative swimming speed (P = 0.23) in the ratfish, whereas the downstroke was significantly faster than the upstroke (P = 0.006). The similar muscle ratio, despite differences in stroke phases, may be explained by physiological or in vivo recruitment differences between abductors and adductors in the ratfish.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".